Battery safety is the point of biggest concern nowadays for any OEM. Battery accidents are increasing day by day. The government is also taking a few steps to ensure battery hazards should not happen. New AIS156 amendments are implemented to cater these issues. Few checks which battery pack manufacturers should do to ensure battery pack safety.

Few Causes of Cells Failure:

Cell Level Failure:

- Inadequate binding material — Polyvinylidene Fluoride (PVDF) or Styrene Butadiene Rubbers (SBR) are used as binding materials because of their excellent adhesion properties. Inadequate or adulteration of binding material affects cell safety.

- Use of improper electrolyte — Lithium Hexafluorophosphate (LiPF6) in Ethyl Carbonate or Methyl Carbonate or Ethyl Methyl Carbonate or Dimethyl Carbonate is used as an electrolyte because of its good ionic conductivity, high boiling point, resistance to temperature fluctuations, and non-reactivity with electrode material. Use of improper electrolytes or electrolytes in improper ratio can create a major issue in cell manufacturing which can lead to cell failure.

- Use of sub-standard separator — Separator promotes the movement of ions from the cathode to the anode on the charge and in reverse direction on the discharge and at the same time keeps two electrodes isolated. Separators are generally made up of Polyethylene (PE) or Polypropylene (PP) Nano-fibers. Use of a sub-standard separator can short the cathode and anode and causes fire-like hazards.

- Not using Additive materials — Vinylene Carbonate (VC), Fluoroethylene Carbonate (FEC), Pyridine Boron Trifluoride (PBF), & Pyridine Phosphorus Pentafluoride (PPF) have been commonly used as additives to modify Solid Electrolyte Interface (SEI) layer, improve capacity retention and decrease impedance growth. Not using these materials can degrade the cell faster.

BMS Level Failures also lead to cell or pack-level failures. Some causes of BMS-level failures are:

Hardware Level:

- Use of low-quality MOSFETs which are not properly specked as per current or voltage used.

- Low-quality PCB board manufacturing like using low-quality copper, thin deposition, burnings, & low-quality solder mask.

- Low-quality PCB assembly process and Quality Assurance like improper components placement, low-quality solder, and no checking after assembly. Low-quality wire usage, connectors improper locking, less circuit protection.

Firmware Level:

- Sensor detection failure, AFE failure, memory leaks, rare conditions in the code, not well-defined protection priority order.

All of the above factors can lead to battery hazards. In the above problems, we can easily cater to BMS-level problems because we can make BMS in-house or do a proper quality check at different points. But in the case of cells, cell manufacturers generally don’t share the critical data of binding material, electrolyte composition, separator information, or additives information.

So how to move ahead with cell finalization in that case?

Battery packs have a fixed max C-rate at which the battery will be discharged according to application, hence if we can compute the maximum heat or in other words the max temperature inside the cells in a battery pack when it is discharged at its max C-rate, then it will help us in defining the cut-off temperature for the battery pack.

We can achieve this by physically discharging the battery pack at its max C-rate under different ambient temperatures or we can make use of simulations. In this article, we will be looking into how this can be achieved using simulations.

It is a known fact that it is the electrochemical reactions that take place inside a Li-ion cell that generates heat. So, if we can capture the electrochemical reactions that take place inside a cell when it is discharged at its max C-rate, it will serve our purpose of determining the max heat generated inside the cell. Also, the heat generated, and temperature computed will be more accurate.

Electrochemical modeling demands cell chemistry level data such as the Volume fraction of electrolytes, the activation energy of positive and negative electrodes, and so on. Usually, the cell manufacturers won’t share this data, hence it becomes a challenging task to do electrochemical modeling of the cells.

So, at this point we can make use of equivalent circuit models, these equivalent circuit models can capture the dynamics of a cell.

Below shown is a 2 RC branch equivalent circuit model,

Parameters of the above equivalent circuit viz, Voc, V0, R1, C1, R2, C2 if computed, can be used in determining the heat generated in a Li-ion cell.

The heat generated is a function of Voc (open-circuit voltage), V (Cell voltage), and one more function dU/dt (this is computed using the remaining parameters of the equivalent circuit model).

So now the question arises that how we can determine the parameters of the equivalent circuit model, the answer to this question is the Hybrid Pulse Power Characterization test (HPPC testing) of the cell.

HPPC test generally consists of a pulse discharge and pulse charge, but to compute the parameters of the equivalent circuit model for a discharging cell no need for pulse charging, only pulse discharge is required.

HPPC test (pulse discharge) of the cell can be conducted at different ambient temperatures.

The procedure of the HPPC test is as follows,

1. Keep the cell in a thermostat and set the required ambient temperature.

2. Charge the cell to its max voltage (100% SoC) as per the cell manufacturer's recommended method.

3. Discharge the cell to the next SoC at a particular C-rate (Pulse current). Pulse current can be applied for a few seconds to a few minutes

4. Rest for 1 hour.

5. Repeat steps 3 to 4 until the DOD is 90%.

Discharge pulse current, the SoC steps at which pulse discharge needs to be done can be determined as per our requirements. If we want the finer details on the dynamics of a cell, we can go for a greater number of SoC points and pulse discharge in terms of minutes.

A typical Pulse discharge profile at a particular SoC looks as shown below,

Such profiles are generated for a set of equally spaced SoC points, and the parameters of the equivalent circuit are calculated using a non-linear curve fitting

A typical curve-fitting profile is shown below for reference,

One can check the percentage of curve fitting achieved and can also improvise the curve fitting by using 3 or 4 RC branch circuits in the equivalent circuit model.

Better the curve fitting, the more accurate will be the calculated equivalent circuit parameters.

Generally, with 2 RC circuits, we can achieve a fair amount of curve fitting.

Once we are successful with curve fitting and calculating the equivalent circuit parameters, we can run transient (Time based) simulations to determine the max heat generated, and max temperature in the battery pack.

Below is the temperature plot and temperature contour plot that we can obtain from simulations,

We can also get the voltage variation plot of the cell,

These simulations will give the tentative idea of temperature rise and voltage fluctuations in the cell and pack at different ambient temperatures and different C-rates. We can conclude our design and finalize the cell and design after running the simulations which will help reduce battery heating and hazards at further levels.

Impact of COVID-19 on Auto Industry of India

Auto Industry is one of the critical industries for the Indian economy. It is responsible for 50% manufacturing GDP, 7% gross GDP and 15% of GST collection of India. It benefits around 8 million direct and 40 million indirect people. This massive blow of pandemic will undoubtedly create some problems for the Auto Industry as well as the Indian economy, which was already struggling from 2018 and was hoping to recover in the future.

Impact on Internal Combustion Engine (ICE) vehicles

Sales of ICE vehicles are estimated to go down by almost 40 percent post-COVID situation. 2Ws and entry-level Passenger Vehicles (PVs) will face the lesser blow than 3Ws, SUVs, and Medium & Heavy Commercial Vehicles (M&HCV), because people will be afraid of using public transport or vehicles sharing modes for some more time due to more vulnerability of catching the infection and people, will try to buy more & more affordable means of personal vehicles because the economics on the demand side is also not good. M&HCVs are extensively used in sectors like urban and national highways infrastructure like roads, bridges, construction, mining, goods transportation, etc. But the slowdown in these works is also going to affect the M&HCV directly. Only tractor division is showing some positive signs as the agriculture sector is in good shape and also sufficient rain is predicted on time throughout the country this year.

Major challenges for the ICE sector

All ICE vehicles were supposed to switch to BSVI norms from the 1st of April 2020. Almost Rs 300 billion were invested by the auto industry of India for upgrading to BSVI norms as it requires some modification in the exhaust, particulate matter filter, catalytic convertors, etc. to reduce Carbon monoxide, Sulphur, NOx, and Particulate Matter (PM) from the vehicles.

As the industry was shifting towards BSVI, many dealers have purchased a large inventory of vehicles of BSIV anticipating the good sale of these vehicles on the auspicious occasions of Gudi Padwa or Ugadi which was on 25th of March. But the lockdown has spoiled the play. Despite heavy discounting, almost 5 lacs units of around Rs 6400 Crore BSIV vehicles remained unsold. 2Ws had a major chunk in that.

Because of these situations, the Honorable Supreme Court (SC) of India allowed automobile dealers to sell 10 percent of BSIV inventory for 10 days after lockdown is officially lifted, which is not going to help a lot.

Impact on Electric Vehicles (EVs)

EVs pace will also remain stagnant for at least the next 1–2 years from now. But still, EVs and EV components like Motors, Batteries, Controllers, and Battery Management Systems (BMS) companies are going to bounce back very strong. They have a great future in the long term as India is falling in rankings of climate risk index every year and only EVs can help in dealing with this situation.

Similar to ICE vehicles, 2Ws EVs are not going to face much blow, but 3Ws and PVs can face many issues. E-busses companies require more government support to sustain so they may also go through a pause as State Transport Undertakings (STUs) may not have sufficient funds for procurement. Also, a downward trend in fuel prices in the international market and supply chain disruption can impact the current demand for EVs because the Government will not focus on EVs now as they can recover the economic loss from petrol and diesel taxes at a rapid rate.

Major challenges for rapid EV adoption

• Lack of charging infrastructure is one of the huge problems in India. India has only around 1000 charging stations in comparison with 500000 stations in China. Even a small country like Norway has about 10000 charging stations. The news of the Indian Government early this year of sanctioning 2636 charging stations in 62 cities is a positive sign, but the number is still way shorter than other countries.
• Range anxiety and time is taken to charge the EVs is much more than ICE vehicles.
• The cost of the battery is also one of the hurdles in EV adoption. Almost 35–40 percent of the cost of EVs consists of the battery only. The reason behind it is we don’t have Lithium ores in our country. We need to outsource it. Though we have found some Lithium reserves near Bangalore in Karnataka, it’s decidedly less to fulfil our needs.
• Faster Adoption & Manufacturing of Electric & Hybrid Vehicles (FAME II) is a policy in which Government has sanctioned incentives of Rs 8596 Crores which can help EV & component manufacturer, but the duration of the policy is just 3 years which is not a long time to get a product once you start. There must be little more predictability in the policy time.

What companies can do to cope up with this situation

• We import 27% of ICE auto components from China. Minor tensions in this relationship can make us pay a hefty price. So, companies should reduce dependency on one particular country and search for different vendors from different geographies.
• We import fuel injectors, Exhaust gas recirculation (EGR) modules, Electronic components, Airbag components, Plastic materials, and some body part’s moulds, etc. Our auto ancillary companies should look at some of these components to make it in-house at a competitive price.
• Companies should do some value addition for consumers like online booking of vehicles, home delivery of vehicles and test rides in this situation.
• If the vehicle is used as a taxi vehicle, then in those models companies can add or provide Nano-Disinfectants, Thermal scanners behind the seats, etc. for confidence building and safety of the customers and driver.
• Service centres should give on-call customer support for maintenance and servicing.
• EV battery companies should partner more with the counterparts of other countries for sourcing Lithium at a cheaper rate.
• EV companies should try to build maximum parts in-house to make EVs with better-built quality.
• Avoid lay-offs of your people as much as you can. Opt for salary cuts, keep sacking as the last option because people are more important than the product. You can always develop or emulate a product, but you can’t imitate the spirit, dedication, devotion, loyalty of your people for your cause.

What Government should do to help Auto-Industry of India to faster recovery

• The Government must provide certain subsidies or tax benefits on the manufacturing of individual parts which we import more. Because OEMs import from China not because they like to but because they don’t have a choice.
• Increase construction, road/highway building projects to roll the economy properly and help M&HCV bounce back fast in the market
• Appeal to Honorable SC for extension of BSVI transition date by at least 6 months which will help dealerships and companies to clear the BSIV stock and come out of the liquidity crunch.
• Make available BSVI fuel everywhere before 100 percent transition because BSIV fuel can cause problems to the BSVI engine (at least in Diesel vehicles) because of the difference in Sulphur content in the fuels which may affect the fuel delivery valves.
• Increase the time of FAME II policy incentives until 2025 at least.
• Try to invest more in Lithium mines in countries like Australia, Bolivia, and Chile, etc. to reduce the cost of EVs and search for its reserves in India as well.
• Give more emphasis on building Battery Swapping Stations and Fast Charging Stations in ample numbers.

How prepared is The Electric Vehicle Industry of India for The Government’s target of 2030?

India largely depends on the import of crude oil to meet most of its mobility fuel needs. Today India’s oil dependence is 83.7% (in 2018–19) according to the oil ministry’s Petroleum Planning & Analysis Cell (PPAC). India can save 64% of mobility-related energy demand by 2030 by pursuing a shared, electric and connected solutions. This could reduce oil dependency and can help increase in GDP by around 1%. But at what extent the EV industry is prepared for the government’s target for 2030. Let’s first know the government’s target for electric vehicles by 2030

• Converting all the 3 wheelers running in the country to all-electric by 2023.
• Converting ICE 2 wheelers below 150cc to electric by 2025.
• Converting 30% ICE 4 wheelers & other heavy vehicles to electric by 2030.

If we see the current statistics of Indian vehicles, we have

• 79% of 2 wheelers
• 4% tempos & 3 wheelers
• 3% bus & trucks
• 12% passenger vehicles below 10 Lakhs
• 2% passenger vehicles above 10 Lakhs

Now, 79% corresponds to around 170 million vehicles. As of now, the presence of EV is not even 1%. So, despite so much push, there is a lot of ground to cover for the shift to EVs and shift from 1% to almost 70% within such a limited span of time is very tough. We also don’t have a charging infrastructure in place, which is essential for this transition. According to current scenario & various surveys on auto companies, we can achieve 40%-45% of this target by 2030 if we keep emphasizing on EVs with same intent & extent and 40–45% is also a very good number to achieve.

What are the major bottlenecks

• Charging Infrastructure — One of the biggest bottlenecks is lack of charging infrastructure like regular charging, fast charging & Battery swapping. If we want to attain our goal, we must have a charging point at every single kilometre and some battery swapping stations at every 8–10 kilometres. A lot of companies are coming in and working on charging infrastructure, but their efforts should be collaborative with Indian government because there will be some changes required in distribution transformers for the growing charging infrastructure need and also the harmonic distortions due to EV charging may impact the grid stability. Working on these issues can take a significant amount of cost, time and efforts. The government might also want to think and research on technologies like Dynamic EV charging to improve the range of the vehicle to cut range anxiety in users.
• Li-ion Prices — Almost 35–40% of the cost of EVs is comprised of the battery only. Although India has the 2nd largest presence of graphite material after China, still, India doesn’t have access to some essential elements like Lithium, Cobalt & Nickel. Lithium is mostly available in countries like Chile, Bolivia, Argentina, Australia, Zimbabwe, Portugal, Brazil, and some parts of the US and China. Cobalt has its major shares in DRC (Democratic Republic of Congo) & around 25% of the world’s Nickel deposition is in Indonesia. Like China, we haven’t started owning the mines in these critical regions yet. Investments in these areas and localisation of Li-ion battery making is very essential to cut down the prices of EV in comparison to ICE vehicles. Though the cost of the operations of EV is much lesser than that of ICE vehicles. But the capital cost is more, that’s why people hesitate to buy EVs, and it’s very important to help people buy a vehicle because it is not manufacturers or policymakers who shape the market its consumers or users who does.
• Employment issues — Because of a lot of opportunity in this domain & charging infrastructure, a large amount of job creation will happen. It is predicted that about 5 lakhs — 8.5 lakhs jobs will be created by 2030 because of EVs transition but converting existing jobs is going to be very tough. Today auto industry contributes around 49% to manufacturing GDP & gives employment to around 37 million people further auto ancillary company employees to around 3 million people, and they receive almost 50% of revenue from the parts of Engine & Drivetrain. Also, ICE 4 wheelers contain about 30000 parts, and 2 wheelers contain around 3000 parts in comparison with EVs, which will have around 1000 & 300 parts, respectively. Now, this sharp shift to EVs will create a lot of existing employment issues when India is actually under a job crisis. Planning this situation out is going to be an arduous task for the government.

What the government can do more

Government is making some good policies for positive engagement of EVs in the Indian ecosystem. Recently, the government announced a FAME II scheme (Faster Adoption & Manufacturing of Electric & Hybrid Vehicles) in which government has sanctioned incentives of Rs 8596 Crores. A crucial clause in it is that the only companies that meet the 50% localization threshold will be eligible for the incentives. Currently, more than 95% of companies are just trading EVs, buying it from China & selling it here. Because of this clause, the government is encouraging the manufacturing of EVs in India, which will also help job creation. But the duration of FAME II is for three years, which is not a long time to get a new product once you start. There must be little more predictability in policy at least like 6–7 years then only it will allow OEMs and Vendors to invest. Also on the charging side of 2 wheelers, there is a lack of standardization in terms of charging protocols. So, it doesn’t allow people to make investments. So there is a high need for standardizing it. Also, rather than imposing policy on the complete country, it is more convenient to do it on a certain sample set and then expanding it slowly on the complete province.

The arrival of Li-ion batteries has been nothing short of a blessing in the world of technology and gadgets. These batteries are more energy dense compared to both Lead acid and Nickel Metal Hydride. That’s why Li-ion cells are widely used in Automotive, Laptops & Cameras, and other Electronics equipment nowadays. India recently started venturing into manufacturing of Li-ion batteries with some policy push by the Indian Government. But can India surpass the Chinese market in production and pricing with the current scenario?

What does precisely lithium-ion battery consist of?

Cathode Current Collector — Based on electronic conductivity and potential stability, Aluminium foil is most widely used as lithium-ion battery cathode current collector.

Anode Current Collector — Copper foil is mostly used as lithium-ion battery anode current collector.

Cathode Active material / Lithium Transition Metal Oxide — NMC — (Lithium Nickel Cobalt Manganese, LiNiCoMnO2), LFP — (Lithium Iron Phosphate, LiFePO4), NCA — (Lithium Nickel Cobalt Aluminium Oxide, LiNiCoAlO2), LMO — (Lithium Manganese Oxide, LiMn2O4), LNMO — (Lithium Nickel Manganese Spinel, LiNi1/2Mn3/2O4), LCO — (Lithium Cobalt Oxide — LiCoO2) are six types of cathode material widely used in Li-ion batteries. Also, an in-depth research is going on Lithium-Air and Lithium Sulfur material, which can have four times the energy density than the materials mentioned earlier. In all the types of chemistries mentioned above, NMC is the most widely used in Automobiles. So, let’s take the reference of NMC chemistry in the comparison.

Anode Active material — Graphite, Graphene and Silicon can be used as the anode material of the Li-ion battery. Graphene and Silicon are still on a naive stage of studies. Graphite is most commonly used as anode active material because it can reversibly place Lithium ions between its many layers.

Electrolyte — Lithium Hexafluorophosphate (LiPF6) in Ethyl Carbonate or Methyl Carbonate or Ethyl Methyl Carbonate or Dimethyl Carbonate is used as an electrolyte in Li-ion batteries because of its good ionic conductivity, high boiling point, resistance to temperature fluctuations and non-reactivity with the electrode material.

Additives — Vinylene Carbonate (VC), Fluoroethylene Carbonate (FEC), Pyridine Boron Trifluoride (PBF), & Pyridine Phosphorus Pentafluoride (PPF) have been commonly used as additives to modify Solid Electrolyte Interface (SEI) layer, improve capacity retention and decrease impedance growth.

Separator — Separator promotes the movement of ions from the cathode to the anode on the charge and in reverse direction on the discharge and at the same time keeps two electrodes isolated. Separators are generally made up of Polyethylene (PE) or Polypropylene (PP) Nano-fibers.

Binder — Polyvinylidene Fluoride (PVDF) and Styrene Butadiene Rubbers (SBR) are used as binding materials because of its excellent adhesion properties.

Housing — PVC wraps, Nickel ribbons, Tabs, Caps and End Plates make a housing assembly of Li-ion battery pack.

Pie Chart shows the percentage weight distribution of every element. Approximate weight of single Li-ion cell generally varies from 45gms to 50gms.

Comparison between China and India

Now if we consider the materials required such as a cathode current and anode current collector, electrolytes, additives, separator, binder and housing, both the countries can manage to make it in approximately the same cost.

Now, let’s consider the major elements in the Li-ion battery. In the case of active anode material ‘graphite’, 65% of graphite in the world is mined in China, followed by 12.5% in India. Both the countries are graphite-rich, so graphite is very readily available in both the countries and labour cost in both countries is almost similar.

‘Lithium’ the core element of the battery has its presence in Chile, Argentina, Bolivia, Australia, Zimbabwe, Portugal, Brazil, some small areas of the United States and China. India doesn’t have any lithium source. India has to import this material from the countries mentioned previously, which is a very costly affair.

Democratic Republic of Congo, a country situated in central Africa is one of the most significant lands in the world where the Cobalt element is abundantly found. Interestingly, some of the prominent industrialists from China has bought many mines in DRC so that they can mine and get the cobalt very easily. India hasn’t yet started any investment in the countries like DRC to acquire the essential elements required to make Lithium-ion batteries. So, importing cobalt easily and at a reasonable rate compared to China is quite complicated and expensive for India.

Indonesia contains the major portion of Nickel in the world, which is geographically closer to China than India. So importing Nickel from Indonesia is more advantageous to China and little economical than compared to India.

Therefore by analysing the current scenario carefully, it is intelligible that making Li-ion batteries is plain sailing and affordable to China than India. It will be difficult for India to beat the Chinese market at this moment in Lithium-ion cell manufacturing and it’s pricing.

So, what is the solution?

Competing with China in Li-ion cell manufacturing and its pricing is challenging but if big players in Indian industries manage to acquire Lithium and Cobalt mines in various countries it will be easy to get these scarce and vital elements and can propel the cell manufacturing business in the country.

Another alternative is, India focuses its resources more on research on Sodium Air or Sodium cell batteries and creates some radical improvements in this technology. This technology has the potential of outperforming Li-ion Technology in future. Also, sodium resources are abundantly available in India compared to the lithium sources, which can shift the needle in India’s favour.

Can India beat China in Li-ion battery manufacturing and its pricing? was originally published in Dialogue & Discourse on Medium, where people are continuing the conversation by highlighting and responding to this story.